X-ray computerized tomography apparatus, breathing indication apparatus and medical imaging apparatus

ABSTRACT

An X-ray computed tomographic apparatus includes a gantry  100  including an X-ray tube  101  which generates X-rays and an X-ray detector  103  which detects X-rays transmitted through a subject to be examined, a reconstruction device  114  which generates tomogram data on the basis of an output from the X-ray detector, a breath detector  203  which detects a respiration waveform representing a temporal change in respiration index value associated with the subject, a regular respiration waveform generating unit  207  which generates a respiration waveform with a regular respiration cycle which originates from the detected respiration waveform, and a gantry mount display  201  which displays the generated regular respiration waveform.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Applications No. 2006-277886, filed Oct. 11, 2006;No. 2006-282844, filed Oct. 17, 2006; and No. 2006-282845, filed Oct.17, 2006, the entire contents of all of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an X-ray computed tomographicapparatus, breath instruction apparatus, and medical imaging apparatuswhich generate medical images by imaging a subject to be examined.

2. Description of the Related Art

Stable breathing is indispensable for improving image quality byreducing artifacts. Conventionally, in order to stabilize breathingmotion, an operator gives a subject to be examined spoken instructionsfrom an operator room through a microphone. It is, however, difficult tostabilize breathing motion by spoken instructions. Furthermore, anoperator who has not comprehended the stable breathing of a subject mayunstabilize the breathing of the subject by giving him/her inappropriateinstructions. See Jpn. Pat. Appln. KOKAI Publication No. 2003-265464.

Conventionally, an X-ray computed tomographic apparatus uses an imagingmethod and reconstruction method which require the electrocardiographiccomplex of a subject, such as an ECG-gated scanning method and anECG-gated reconstruction method. However, a conventional X-ray computedtomographic apparatus does not allow to check how electrocardiogramshave been captured, and hence may not be properly ECG-gated. Inoperation except ECG-gated imaging or ECG-gated reconstruction, it ispreferable in terms of reduction in artifacts to perform scanning in aperiod during which the heart rate is stable. It is, however, impossibleto check this. The operator therefore starts scanning upon determining astable period by checking the heart rate according to his/herexperience. See Jpn. Pat. Appln. KOKAI Publication No. 2003-265464.

In addition, conventionally, a subject is instructed by voice how to actduring examination. For example, the automatic voice playback device ofan apparatus gives a spoken instruction to hold a breath or a spokeninstruction not to move, or the operator gives such instructions byhuman voice through a microphone. The subject totally depends on voicewhen acquiring information, and cannot know any information about theremaining time of breath holding, the remaining time of examination, andthe like without voice. This may cause a situation in which the subjectfeels insecure. In addition, in imaging operation, it is preferable interm of reduction in body movement artifacts that a subject keeps quietand relaxed and stabilizes his/her heartbeat and breath as much aspossible. However, conventional apparatuses have not been provided withany techniques for making subjects feel relaxed. See Jpn. Pat. Appln.KOKAI Publication No. 2003-265464.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to promote stabilizing thebreathing motion of a subject to be examined.

It is another object of the present invention to provide informationwhich allows to objectively check how electrocardiograms are captured orthe cardiac motion is stabilized.

An X-ray computed tomographic apparatus in accordance with first aspectof the present invention includes a gantry including an X-ray tube whichgenerates X-rays and an X-ray detector which detects X-rays transmittedthrough a subject to be examined, a reconstruction device whichgenerates tomogram data on the basis of an output from the X-raydetector, a breath detector which detects a respiration waveformrepresenting a temporal change in respiration index value associatedwith the subject, a regular respiration waveform generating unit whichgenerates a respiration waveform with a regular respiration cycle whichoriginates from the detected respiration waveform, and a gantry mountdisplay which displays the generated regular respiration waveform.

A medical imaging apparatus in accordance with second aspect of thepresent invention includes an image generating unit which generatesimage data by imaging a subject to be examined; a breath detecting unitwhich detects a respiration waveform representing a temporal change inrespiration index value associated with the subject; a regularrespiration waveform generating unit which generates a respirationwaveform with a regular respiration cycle which originates from thedetected respiration waveform; and a breath instruction unit whichprovides breath instruction information on the basis of the generatedregular respiration waveform.

A breath instruction apparatus in accordance with third aspect of thepresent invention includes a breath detecting unit which detects arespiration waveform representing a temporal change in respiration indexvalue associated with a subject to be examined; a regular respirationwaveform generating unit which generates a respiration waveform with aregular respiration cycle which originates from the detected respirationwaveform; and a display unit which displays the generated regularrespiration waveform.

An X-ray computed tomographic apparatus in accordance with fourth aspectof the present invention includes a gantry including an X-ray tube whichgenerates X-rays and an X-ray detector which detects X-rays transmittedthrough a subject to be examined; a tomogram generating unit whichgenerates tomogram data on the basis of an output from the X-raydetector; a cardiac index calculating unit which instantly calculates aplurality of cardiac indexes associated with a heartbeat state on thebasis of an electrocardiogram associated with the subject; a cardiacindex selection unit which selects at least one cardiac index among theplurality of calculated cardiac indexes in accordance with a userinstruction; and a display unit which is held on a housing of the gantrydirectly or through an arm and instantly displays the selected cardiacindex.

An X-ray computed tomographic apparatus in accordance with fifth aspectof the present invention includes a gantry including an X-ray tube whichgenerates X-rays and an X-ray detector which detects X-rays transmittedthrough a subject to be examined; a tomogram generating unit whichgenerates tomogram data on the basis of an output from the X-raydetector; a file storage unit which stores a plurality of audio filesand a plurality of image files which are associated with instructions tothe subject; an information storage unit which stores informationassociating the audio file and the image file with each of a pluralityof examination stages; an instruction information providing unit whichprovides instruction information to the subject on the basis of theaudio file and the image file which are associated with an examinationstage in accordance with a progress of the examination; and a changingunit which changes the association information in accordance with a userinstruction.

A medical imaging apparatus in accordance with sixth aspect of thepresent invention includes an image generating unit which generatesimage data by imaging a subject to be examined; a file storage unitwhich stores a plurality of audio files and a plurality of image fileswhich are associated with instructions to the subject; an informationstorage unit which stores information associating the audio file and theimage file with each of a plurality of examination stages; aninstruction information providing unit which provides instructioninformation to the subject on the basis of the audio file and the imagefile which are associated with an examination stage in accordance with aprogress of the examination; and a changing unit which changes theassociation information in accordance with a user instruction.

An X-ray computed tomographic apparatus in accordance with seventhaspect of the present invention includes, which scans a subject to beexamined with X-rays, acquires projection data, and reconstructs animage, and a respiration navigation apparatus which guides respirationoperation for the subject, the respiration navigation apparatusincluding a storage unit which stores a plurality of respiration guidedata files for guiding the respiration operation, a read control unitwhich selectively reads out the respiration guide data file from thestorage unit in accordance with a control signal from the X-ray computedtomographic apparatus, and a display unit which displays the readoutrespiration guide data file, and the X-ray computed tomographicapparatus including a control signal generating unit which controlsscanning of the subject and generates the control signal in synchronismwith control on the scanning, and a display unit which displays a timeof generation of the control signal, a type of the control signal, andan execution result.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a block diagram showing the arrangement of an X-ray computedtomographic apparatus according to an embodiment of the presentinvention;

FIG. 2 is a view showing the mount position of a gantry mount display inFIG. 1 on a gantry;

FIG. 3 is a view showing another example of the mount position of thegantry mount display in FIG. 1 on the gantry;

FIG. 4 is a timing chart showing an example of a respiration waveformdetected by a breath detector in FIG. 1;

FIG. 5 is a chart showing a first method of generating a regularrespiration waveform by a regular respiration waveform generating unitin FIG. 1;

FIG. 6 is a chart showing a second method of generating a regularrespiration waveform by the regular respiration waveform generating unitin FIG. 1;

FIG. 7 is a chart showing a third method of generating a regularrespiration waveform by the regular respiration waveform generating unitin FIG. 1;

FIG. 8 is a view showing a display example of the gantry mount displayin FIG. 1;

FIG. 9 is a block diagram showing the arrangement of an X-ray computedtomographic apparatus according to another embodiment of the presentinvention;

FIG. 10 is a view showing the mount position of a gantry mount displayin FIG. 9 on a gantry;

FIG. 11 is a view showing another example of the mount position of thegantry mount display in FIG. 9 on the gantry;

FIG. 12 is a view showing a display example of the gantry mount displayin FIG. 9;

FIG. 13 is a view showing a display item designation window exampleprovided by a display layout support unit in FIG. 9;

FIG. 14 is a view showing a display layout design window exampleprovided by the display layout support unit in FIG. 9;

FIG. 15 is a view showing an example of operation on the display layoutdesign window in FIG. 14;

FIG. 16 is a block diagram showing the arrangement of an X-ray computedtomographic apparatus according to still another embodiment of thepresent invention;

FIG. 17 is a view showing an example of a gantry and a display mountedthereon;

FIG. 18 is a view showing another example of the gantry and the displaymounted thereon;

FIG. 19 is a view showing an example of a display window on a gantrymount display comprising a display window forming unit in FIG. 16;

FIG. 20 is a view showing another example of the display window on thegantry mount display comprising the display window forming unit in FIG.16;

FIG. 21 is a view showing an example of a display item stored in adisplay item storage unit in FIG. 16;

FIG. 22 is a view showing another example of the display item stored inthe display item storage unit in FIG. 16;

FIG. 23 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 24 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 25 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 26 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 27 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 28 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 29 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 30 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 31 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 32 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 33 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 34 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 35 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 36 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 37 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 38 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 39 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 40 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 41 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIG. 42 is a view showing still another example of the display itemstored in the display item storage unit in FIG. 16;

FIGS. 43A, 43B, 43C, and 43D are views each showing an example of abreath holding instruction image (guidance image);

FIG. 44 is a view showing an example of an image indicating the progressof examination;

FIG. 45 is a block diagram showing a user navigation system as amodification, together with an X-ray CT apparatus; and

FIG. 46 is a view showing an example of an examination informationwindow displayed on the screen of the display device or operation deviceof the X-ray CT apparatus in FIG. 45.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

An embodiment of an X-ray computed tomographic apparatus according tothe present invention will be described below with reference to theviews of the accompanying drawing. Note that the present invention isnot limited to an X-ray computed tomographic apparatus and can beapplied to other medical imaging apparatuses which generate imagesassociated with a subject to be examined, e.g., an X-ray diagnosticapparatus, magnetic resonance imaging apparatus (MRI), ultrasonicdiagnostic apparatus, and gamma camera. The present invention can alsobe applied to a breath instruction apparatus specialized as a breathinstruction function. An X-ray computed tomographic apparatus will beexemplified below. Note that X-ray computed tomographic apparatusesinclude various types of apparatuses, e.g., a rotate/rotate-typeapparatus in which an X-ray tube and an X-ray detector rotate togetheraround a subject to be examined, and a stationary/rotate-type apparatusin which many detection elements are arrayed in the form of a ring, andonly an X-ray tube rotates around a subject to be examined. The presentinvention can be applied to either type. In this case, the rotate/rotatetype, which is currently the mainstream, will be exemplified. In orderto reconstruct one-slice tomogram data, projection data corresponding toone rotation around a subject to be examined, i.e., about 360°, isrequired, or (180°+view angle) projection data is required in the halfscan method. The present invention can be applied to either of thesereconstruction schemes. As mechanisms of converting incident X-rays intoelectric charges, the following techniques are the mainstream: anindirect conversion type that converts X-rays into light through aphosphor such as a scintillator and converts the light into electriccharges through photoelectric conversion elements such as photodiodes,and a direct conversion type that uses generation of electron-hole pairsin a semiconductor by X-rays and migration of the electron-hole pairs toan electrode, i.e., a photoconductive phenomenon. As an X-ray detectionelement, either of these schemes can be used. In this case, the formertype, i.e., the indirect conversion type, will be exemplified. Recently,with advances toward the commercialization of a so-called multi-tubetype X-ray computed tomographic apparatus having a plurality of pairs ofX-ray tubes and X-ray detectors mounted on a rotating ring, relatedtechniques have been developed. The present invention can be applied toboth a conventional single-tube type X-ray computed tomographicapparatus and a multi-tube type X-ray computed tomographic apparatus.The single-tube type X-ray computed tomographic apparatus will beexemplified here.

FIG. 1 shows the arrangement of the main part of an X-ray computedtomographic apparatus according to this embodiment. The X-ray computedtomographic apparatus according to this embodiment includes a gantry100. The gantry 100 includes an annular rotating frame 102. A rotationdriving unit 107 drives/rotates the rotating frame 102 about a rotationaxis RA. An X-ray tube 101 and an X-ray detector 103 are mounted on therotating frame 102. The X-ray tube 101 faces the X-ray detector 103through the rotation axis RA. The X-ray tube 101 receives a tube voltageand filament current from a high voltage generator 109 through a slipring 108, and generates X-rays. The X-ray detector 103 detects X-raystransmitted through the subject and outputs an electrical signalreflecting the dose of incident X-rays. A preprocessing device 106receives a signal (pure raw data) output from the X-ray detector 103through a data acquisition circuit 104 and a noncontact datatransmission device 105. In the preprocessing device 106, a data storagedevice 112 stores data having undergone sensitivity correction,logarithmic transformation, and the like (called projection data or rawdata).

A breath detector 203 and a microphone 204 are provided on or near thegantry 100. The breath detector 203 detects the breathing motion of thesubject and outputs data associated with a respiration index value orequivalent data (to be simply referred to as breath data hereinafter).The data storage device 112 stores the breath data. Various kinds ofbreath detection methods, e.g., methods of measuring a respiratory flowrate and flow, are available. Assume that in this embodiment, a methodusing the thickness of the chest of a subject which periodically changesin accordance with breathing motion is used as a simple method in whichthe psychological burden on the subject is light. The microphone 204 isprovided to detect mainly the respiratory sound of the subject. Thisrespiratory sound is recorded and played back as a respiration guidethrough a loudspeaker unit 202 together with the display of a regularrespiration waveform.

A gantry mount display 201 is placed on or near the gantry 100. Morespecifically, as shown in FIG. 2, the gantry mount display 201comprising a liquid crystal panel and the like is placed on the housingsurface of the gantry 100 at a position where the display does notbecome an X-ray blockage and can be visually recognized by the subjectinserted into an opening portion 208, typically a cone-shaped portionaround the opening portion 208. As shown in FIG. 3, the gantry mountdisplay 201 may be suspended from the gantry 100 through an articulatedarm 221. The gantry loudspeaker unit 202 is placed on or near the gantry100. More specifically, the gantry loudspeaker unit 202 is placed on thehousing surface of the gantry 100 at a position where the loudspeakerunit does not become an X-ray blockage and the subject inserted in theopening portion can easily hear, typically a cone-shaped portion aroundthe opening portion.

A scan controller 110 controls the operations of the rotation drivingunit 107, high voltage generator 109, and the like to perform dataacquisition (scanning). A reconstruction device 114 reconstructstomogram data on the basis of projection data stored in the data storagedevice 112. The display device 116 is provided to display mainlytomogram data. An operation device 115 comprises a keyboard, mouse, andthe like and is used to input operator instructions.

A display/loudspeaker control unit 205 controls the display of a regularrespiration waveform generated by a regular respiration waveformgenerating unit 207 on the gantry mount display 201 and the playbackoutput of regular respiratory sound corresponding to the regularrespiration waveform generated by a regular respiratory sound generatingunit 208 from the gantry loudspeaker unit 202. This embodiment ischaracterized in that a regular respiration waveform is generated andpresented to the subject, and respiratory sound (regular respiratorysound) corresponding to the regular respiration waveform is played backto promote stabilizing the breathing motion of the subject.

FIG. 4 shows an example of a respiration waveform detected by the breathdetector 203. The chest thickness as a respiration index value rapidlyincreases in an inspiration period, becomes maximum at the end of theinspiration period, gradually decreases in an expiration period, andbecomes minimum at the end of the expiration period. In this case, theperiod from the end of an inspiration period to the end of the nextinspiration period is called a respiration period as a unit period, andits time width is defined as a respiration cycle. A partial waveform inone respiration period is defined as a waveform element as a minimumunit of a respiration waveform. In addition, in this embodiment, aperiod from the end of an inspiration period to the lapse of apredetermined fixed time is defined as a window period for determiningwhether breathing motion is stable. Part of a respiration waveformincluded in this window period will be referred to as a waveformportion. Furthermore, a change in chest thickness due to breathingmotion, i.e., the difference between the chest thickness (maximumthickness) at the end of an inspiration period and the chest thickness(minimum thickness) at the end of an expiration period, will be referredto as a respiration depth. As will be described later, a respirationdepth is calculated for each respiration period.

As described above, a characteristic feature of this embodiment is topresent a regular respiration waveform. A regular respiration waveformis a respiration waveform exhibiting that a respiration cycle andvariations in respiration cycle due to a unique respiration waveformgenerated by a subject by himself/herself in a period during which thesubject stably repeats breathing are constant and regular. Essentially,a regular respiration waveform is a waveform with which the subject canperform breathing motion most comfortably. It is especially important togenerate a regular respiration waveform from the respiration waveform ofthe subject himself/herself. Such a waveform can reflect the peculiarway and manner of breathing unique to the subject. This greatly improvesthe effect of promoting stabilizing breathing motion as compared with acase wherein a so-called generalized respiration waveform is presentedupon simple expansion or contraction.

This embodiment presents three kinds of methods of generating regularrespiration waveforms as will be described below. In practice, theregular respiration waveform generating unit 207 uses an arbitrary oneof the generation methods by selectively executing three kinds ofprogram codes corresponding to the three kinds of generation methods inaccordance with an operator instruction. The three kinds of methods ofgenerating regular respiration waveforms will be sequentially describedbelow. Before the generation of a regular respiration waveform, thebreath detector 203 detects the breath of the subject, and the datastorage device 112 stores, for example, respiration data for severalmin. In the same period, the microphone 204 detects the respiratorysound of the subject, and the data storage device 112 stores therespiratory sound data. Typically, a time stamp is used to makerespiration data correspond to respiratory sound data.

FIG. 5 schematically shows a first procedure for generating a regularrespiration waveform. The data storage device 112 supplies respirationdata acquired by the breath detector 203 for at least a period of onemin to the regular respiration waveform generating unit 207. First ofall, the regular respiration waveform generating unit 207 specifies theend of an inspiration period from at least a respiration waveformcorresponding to one min on the basis of the maximum value of therespiration waveform, and divides the entire respiration interval into aplurality of respiration periods. The respiration waveform is thendivided into a plurality of waveform elements in accordance with theplurality of divided respiration periods. The regular respirationwaveform generating unit 207 calculates the respiration cycle andrespiration depth of each of a plurality of waveform elements. The unitthen specifies a respiration cycle with the highest frequency ofappearance among the calculated respiration cycles. The unitalternatively specifies waveform elements with the highest respirationdepths among a plurality of respiration elements corresponding to thespecified respiration cycle with the highest frequency of appearance.The unit generates a regular respiration waveform by combining thespecified waveform elements. Obviously, this regular respirationwaveform has a perfectly constant respiration cycle and respirationdepth. This waveform shape corresponds to a breathing motion unique tothe subject.

The display/loudspeaker control unit 205 forms a respiration guidewindow in accordance with the generated regular respiration waveform,and causes the gantry mount display 201 to display the window. FIG. 8shows an example of a respiration guide window. Note that this windowcomprises a respiration guide display area (A), a display area (B) forproviding instructions for the subject and various kinds of informationassociated with examination and the like, and a display area (C) aimedat both the subject and the operator. The display area (B) displays, asinformation corresponding to the progresses of examination and scan,information such as the remaining time of a scan, an examination timeschedule, and the remaining rest time to a next scan which correspondsto the rest time between a scan and the next scan. The display area (C)displays, for example, patient information, imaging engineerinformation, hospital guide information, and advertisement information.Window construction in the areas (B) and (C) is performed by the controlunit 205 or other constituent elements specialized for the respectiveareas.

In the respiration guide display area (A), a graphic pattern 301 of aregular respiration waveform is displayed as if it flowed from the rightside to the left side with the lapse of the actual time. A respirationguide mark 303 is superimposed on the graphic pattern 301 of the regularrespiration waveform. The horizontal position of the respiration guidemark 303 is fixed at a specific position within the window, and thevertical position of the respiration guide mark 303 vertically moves inaccordance with the flow of the graphic pattern 301 of the regularrespiration waveform. The subject can gradually stabilize his/herbreathing motion by receiving guidance based on the vertical movement ofthe respiration guide mark 303 in accordance with the flow of thegraphic pattern 301 of the regular respiration waveform.

The display/loudspeaker control unit 205 plays back respiratory soundrecorded from the subject through the microphone 204 at the same time ofthe detection of the waveform elements in synchronism with the flow ofthe graphic pattern 301 of the regular respiration waveform and thevertical movement of the respiration guide mark 303, and the loudspeakerunit 202 outputs the sound. This respiratory sound is the one producedby the subject by himself/herself, and can further promote stabilizingthe breathing motion in accordance with the flow of the graphic pattern301 of the regular respiration waveform and the vertical movement of therespiration guide mark 303.

FIG. 6 schematically shows a second procedure for generating a regularrespiration waveform. As described above, the data storage device 112supplies respiration data acquired by the breath detector 203 for atleast a period of one min to the regular respiration waveform generatingunit 207. First of all, the regular respiration waveform generating unit207 specifies the end of an inspiration period from at least arespiration waveform corresponding to one min on the basis of themaximum value of the respiration waveform.

A window period is defined in an interval from the end of each specifiedinspiration period to the end of a predetermined fixed time. A windowperiod can be arbitrarily adjusted by the operator, and is set to have awidth large enough to include at least three respiration periods,typically five to ten sec. Variations in respiration cycle andrespiration depth are calculated for each window period. A variation inrespiration cycle is calculated as the difference between the longestrespiration cycle and the shortest respiration cycle among a pluralityof respiration periods included in a window period. A variation inrespiration depth is calculated as the difference between the largestrespiration depth and the smallest respiration depth in a plurality ofrespiration periods included in a window period.

The regular respiration waveform generating unit 207 narrows down aplurality of waveform portions corresponding to a plurality of windowperiods into a plurality of waveform portions exhibiting respirationdepths equal to or more than a given depth, i.e., a given threshold, andspecifies a waveform portion exhibiting the smallest variation inrespiration cycle. Note that if there are a plurality of waveformportions exhibiting the smallest variation respiration cycle, a waveformportion exhibiting the largest respiration depth is selected.

This specified waveform portion represents the stablest breathing motionexhibiting a sufficiently large respiration depth and repetition ofrespiration in a predetermined cycle. The specified waveform portionsare combined to generate a regular respiration waveform. As shown inFIG. 8, a respiration guide window is displayed on the gantry mountdisplay 201 under the control of the display/loudspeaker control unit205 in accordance with this regular respiration waveform, as shown inFIG. 8. In addition, the respiratory sound recorded from the subjectthrough the microphone 204 at the same time as the detection of thewaveform portions is played back and output from the loudspeaker unit202 in synchronism with the flow of the graphic pattern 301 of theregular respiration waveform and the vertical movement of therespiration guide mark 303.

FIG. 7 schematically shows a third procedure for generating a regularrespiration waveform. As in the above case, the data storage device 112supplies respiration data acquired by the breath detector 203 for atleast a period of one min to the regular respiration waveform generatingunit 207. First of all, the regular respiration waveform generating unit207 specifies the end of an inspiration period from at least arespiration waveform corresponding to one min on the basis of themaximum value of the respiration waveform. A window period is defined inan interval from the end of each specified inspiration period to the endof a predetermined fixed time. A window period includes at least threerespiration periods. Variations in respiration cycle and respirationdepth are calculated for each window period. A variation in respirationcycle is calculated as the difference between the longest respirationcycle and the shortest respiration cycle among a plurality ofrespiration periods included in a window period. A variation inrespiration depth is calculated as the difference between the largestrespiration depth and the smallest respiration depth in a plurality ofrespiration periods included in a window period.

The regular respiration waveform generating unit 207 narrows down aplurality of waveform portions corresponding to a plurality of windowperiods into a plurality of waveform portions exhibiting respirationdepths equal to or more than a given threshold, and specifies, among thewaveform portions, a predetermined number of waveform portions in orderof increasing variations in respiration cycle, e.g., top three waveformportions in order of increasing variations in respiration cycle.

The regular respiration waveform generating unit 207 averages thesethree specified waveform portions to generate a single specifiedwaveform portion. In averaging these waveform portions, the unitextracts three respiration index values in the same time phase from thethree waveform portions and calculates the average value of the indexvalues. That is, the average waveform portion represents a temporalchange in the average of the three respiration index values.

Note that a processing method of generating a single waveform portionfrom three waveform portions is not limited to averaging processing, andit suffices to, for example, generate a single waveform portion from themedian of three respiration index values in the respective time phasesof three waveform portions or generate a single waveform portion fromthe maximum or minimum value of three respiration index values.

The generated average waveform portions are combined to generate aregular respiration waveform. As shown in FIG. 8, a respiration guidewindow is displayed on the gantry mount display 201 in accordance withthis regular respiration waveform under the control of thedisplay/loudspeaker control unit 205. In addition, respiratory soundrecorded from the subject through the microphone 204 at the same time asthe detection of any of the three waveform portions is played back andoutput from the loudspeaker unit 202 in synchronism with the flow of thegraphic pattern 301 of the regular respiration waveform and the verticalmovement of the respiration guide mark 303. Typically, respiratory soundis played back upon detection of a waveform portion whose variation inrespiration cycle indicates the median of variations in respirationcycle when a waveform portion exhibiting the smallest variation inrespiration cycle and a waveform portion exhibiting the largestvariation in respiration cycle are excluded from the three waveformportions.

As described above, this embodiment has the special effect of promotingstabilizing the breathing motion of a subject by presenting, as arespiration guide, a unique respiration waveform which the subject hasproduced by himself/herself in a period during which he/she stablyrepeats breathing and by playing back the corresponding actualrespiration sound.

Second Embodiment

An embodiment of an X-ray computed tomographic apparatus according tothe present invention will be described below with reference to theviews of the accompanying drawing. Note that the present invention isnot limited to an X-ray computed tomographic apparatus and can beapplied to other medical imaging apparatuses which generate imagesassociated with a subject to be examined, e.g., an X-ray diagnosticapparatus, magnetic resonance imaging apparatus (MRI), ultrasonicdiagnostic apparatus, and gamma camera. The present invention can alsobe applied to an electrocardiographic information display apparatusspecialized as an electrocardiographic information display function. AnX-ray computed tomographic apparatus will be exemplified below. Notethat X-ray computed tomographic apparatuses include various types ofapparatuses, e.g., a rotate/rotate-type apparatus in which an X-ray tubeand an X-ray detector rotate together around a subject to be examined,and a stationary/rotate-type apparatus in which many detection elementsare arrayed in the form of a ring, and only an X-ray tube rotates arounda subject to be examined. The present invention can be applied to eithertype. In order to reconstruct one-slice tomogram data, projection datacorresponding to one rotation around a subject to be examined, i.e.,about 360°, is required, or (180°+view angle) projection data isrequired in the half scan method. The present invention can be appliedto either of these reconstruction schemes. As mechanisms of convertingincident X-rays into electric charges, the following techniques are themainstream: an indirect conversion type that converts X-rays into lightthrough a phosphor such as a scintillator and converts the light intoelectric charges through photoelectric conversion elements such asphotodiodes, and a direct conversion type that uses generation ofelectron-hole pairs in a semiconductor by X-rays and migration of theelectron-hole pairs to an electrode, i.e., a photoconductive phenomenon.As an X-ray detection element, either of these schemes can be used.Recently, with advances toward the commercialization of a so-calledmulti-tube type X-ray computed tomographic apparatus having a pluralityof pairs of X-ray tubes and X-ray detectors mounted on a rotating ring,related techniques have been developed. The present invention can beapplied to both a conventional single-tube type X-ray computedtomographic apparatus and a multi-tube type X-ray computed tomographicapparatus. The single-tube type X-ray computed tomographic apparatuswill be exemplified here.

FIG. 9 shows the arrangement of the main part of an X-ray computedtomographic apparatus according to this embodiment. The X-ray computedtomographic apparatus according to this embodiment includes a gantry1100. The gantry 1100 includes an annular rotating frame 1102. Arotation driving unit 1107 drives/rotates the rotating frame 1102 abouta rotation axis RA. An X-ray tube 1101 and an X-ray detector 1103 aremounted on the rotating frame 1102. The X-ray tube 1101 faces the X-raydetector 1103 through the rotation axis RA. The X-ray tube 1101 receivesa tube voltage and filament current from a high voltage generator 1109through a slip ring 1108, and generates X-rays. The X-ray detector 1103detects X-rays transmitted through the subject and outputs an electricalsignal reflecting the dose of incident X-rays. A preprocessing device1106 receives a signal output from the X-ray detector 1103 through adata acquisition circuit 1104 and a noncontact data transmission device1105. The data output from the data acquisition circuit 1104 isgenerally called pure raw data. The preprocessing device 1106 performspreprocessing such as sensitivity correction and logarithmictransformation for the pure raw data. The preprocessed pure raw data isdata at a stage immediately before reconstruction processing, and isgenerally called projection data or raw data. A data storage device 1112stores the projection data.

An electrocardiograph 1203 is placed on or near the gantry 1100. Theelectrocardiograph 1203 detects an electrical phenomenon accompanyingthe cardiac pulsation of the subject, and generates electrocardiographicdata as a temporal change in the phenomenon. The electrocardiographicdata is supplied to an R wave detecting unit 1206 (to be describedlater) as well as the data storage device 1112.

A gantry mount display 1201 is placed on or near the gantry 1100. Morespecifically, as shown in FIG. 10, the gantry mount display 1201comprising a liquid crystal panel and the like is placed on the housingsurface of the gantry 100 at a position where the display does notbecome an X-ray blockage and can be visually recognized by the subjectinserted into an opening portion 1210 and the operator who stands nearthe gantry 1100, typically a cone-shaped portion around the openingportion 1208. As shown in FIG. 11, the gantry mount display 1201 may besuspended from the gantry 1100 through an articulated arm 1221.

A scan controller 1110 controls the operations of the rotation drivingunit 1107, high voltage generator 1109, and the like to perform dataacquisition (scanning). A reconstruction device 1114 reconstructstomogram data on the basis of projection data stored in the data storagedevice 1112. A display device 1116 is provided to display mainlytomogram data. An operation device 1115 comprises an operation unitwhich includes a keyboard, mouse, and the like and is used to inputoperator instructions, and a display unit for displaying an operationwindow.

A display control unit 1205 is provided to perform processing andcontrol required to lay out display items such as the cardiac indexcalculated by a cardiac index calculating unit 1208 and anelectrocardiogram in accordance with the display layout designed by theoperator through the operation device 1115 under the support of adisplay layout design support unit 1209 and to display the laid-outdisplay items on the gantry mount display 1201. The R wave detectingunit 1206 detects a characteristic wave of the electrocardiogramsupplied from the electrocardiograph 1203, typically an R wave. Acardiac cycle calculating unit 1207 calculates the period of the R wavedetected by the R wave detecting unit 1206, i.e., a cardiac cycle. Thecardiac index calculating unit 1208 calculates a plurality of cardiacindexes associated with the heartbeat state of the subject on the basisof the cardiac cycle calculated by the cardiac cycle calculating unit1207.

The following are examples of the plurality of cardiac indexes which canbe calculated by the cardiac index calculating unit 1208:

heart rate: the number of heartbeats per min, which is calculated foreach cardiac cycle as the value obtained by dividing 60 sec by a cardiaccycle as the time (unit=sec) required for one heartbeat.

interval average heart rate: the average value of a plurality of heartrates repeatedly calculated for every R wave detection (cardiac cyclecalculation) at predetermined intervals, e.g., intervals of 10 sec.

heart rate difference: the value calculated by subtracting a heart ratefrom an interval average heart rate as a value representing a variationin heart rate corresponding to the interval average heart rate.

value calculated by free formula: the value calculated by a formulaarbitrarily set with a heart rate, cardiac cycle, interval average heartrate, heart rate difference, and the like as variables.

The display layout design support unit 1209 performs processing for awindow and associated processing. This window supports the operator todesignate at least one display item, of a plurality of display itemswhich can be displayed, which is to be actually displayed, and to designa display layout indicating how the designated display items arearranged in the display area. Display items include theelectrocardiographic waveform generated by the electrocardiograph 1203,a heart rate history, and a heart rate difference history in addition tothe heart rate, interval average heart rate, heart rate difference, andfree calculation value which are generated by the cardiac indexcalculating unit 1208. A heart rate history is, for example, a latestlist of heart rates corresponding to 10 heartbeats which are directlywritten in numeric form in chronological order. A heart rate differencehistory is a latest list of heart rate differences corresponding to 10heartbeats which are directly written in numeric form in chronologicalorder.

FIG. 12 shows a display window example which is displayed on the gantrymount display 1201 under the control of the display control unit 1205.In the example shown in FIG. 12, a heart rate, heart rate difference,and electrocardiographic waveform are laid out as display items in anelectrocardiographic information area (A). Note that this windowcomprises a display area (B) for providing various kinds of informationassociated with instructions, examination, and the like for the subjectand a display area (C) aimed at both the subject and the operator, inaddition to the electrocardiographic information area (A). The displayarea (B) displays, as information corresponding to the progresses ofexamination and scan, for example, the remaining time of a scan, anexamination time schedule, the remaining rest time to a next scan whichcorresponds to the rest time between the current scan and the next scan.The display area (C) displays, for example, patient information, imagingengineer information, hospital guide information, and advertisementinformation. Window construction in the areas (B) and (C) is performedby the display/loudspeaker control unit 1205 or other constituentelements specialized for the respective areas.

The following is actual operation for displaying electrocardiographicinformation. The electrocardiograph 1203 sequentially detectselectrocardiograms associated with the subject in real time. The R wavedetecting unit 1206 and the cardiac cycle calculating unit 1207sequentially execute R wave detection processing and cardiac cyclecalculation processing, respectively, in real time on the basis of theelectrocardiograms detected in real time. Along with this operation, thecardiac index calculating unit 1208 sequentially calculates a pluralityof cardiac indexes in real time, which are immediately reflected in thedisplay on the gantry mount display 1201. That is, the electrocardiogramdisplayed on the gantry mount display 1201 and the electrocardiographicindex reflect the current heartbeat state of the subject. This allowsthe operator to comprehend the operation state of the electrocardiographitself and the current heartbeat state of the subject. In addition, theoperator can objectively determine from the electrocardiographic indexwhether the heartbeat motion is stable. Such real-time display ofelectrocardiographic information is started before scanning (dataacquisition). The operator then can start scanning operationaccompanying actual generation of X-rays by observing theelectrocardiographic information and pressing a scan trigger button whenthe heartbeat becomes stable to some degree.

FIG. 13 shows a simple display item designation window provided by thedisplay layout design support unit 1209. This window is displayed on thedisplay unit of an operation device 1115 when the operator performsspecific operation through the operation device 1115 to start thedisplay layout design support function. This window displays a list ofnames 1301 of the plurality of display items described above togetherwith check boxes 1302. When the operator checks one or a plurality ofdisplay items which he/she wants to display and clicks the “OK” button,the display control unit 1205 lays out the checked display items inaccordance with default positions and displays them on the gantry mountdisplay 1201. Clicking a “clear” button 1304 will cancel all the checks.Clicking a “details” button 1303 will cause the display layout designsupport unit 1209 to display the detailed display layout design windowshown in FIG. 14 on the display unit of the operation device 1115.

The detailed layout design window shown in FIG. 14 includes a virtualdisplay area 1401 corresponding to the display area (A) of the gantrymount display 201. Boxes 1402 to 1408 indicating display items aredisplayed below the virtual display area 1401. The size ratios of theboxes 1402 to 1408 to the virtual display area 1401 correspond to theratios of the display ranges of the respective display items to thedisplay area (A) of the gantry mount display 1201. As shown in FIG. 15,the operator operates the operation unit of the operation device 1115 todrag and drop at least one of the boxes 1402 to 1408 which correspondsto a display item which the operator wants to display from the displayitem list to a position in the virtual display area 1401 which theoperator wants to display the display item. This operation makes itpossible to complete designation of a display item which the operatorwants to display and design of a display layout. Returning a box fromthe virtual display area 1401 to the display item list will cancel thedisplay designation. All cancellations are made by clicking a “clear”button 1409. When the operator clicks the “OK” button 1410, the displaycontrol unit 1205 displays the display items on the gantry mount display1201 in accordance with the designed layout.

As described above, according to this embodiment, since the latestelectrocardiographic information such as a cardiac index and anelectrocardiogram is always displayed on the gantry mount display 1201,the operator can objectively comprehend the operation state of theelectrocardiograph itself and the current heartbeat state of thesubject. This makes it possible to properly measure the timing ofpressing the scan trigger button.

Third Embodiment

An embodiment of a medical imaging apparatus according to the presentinvention will be described below with reference to the views of theaccompanying drawing. Note that medical imaging apparatuses whichgenerate images associated with a subject to be examined include anX-ray diagnostic apparatus, X-ray computed tomographic apparatus (X-rayCT apparatus), magnetic resonance imaging apparatus (MRI), ultrasonicdiagnostic apparatus, gamma camera, and the like. In this case, an X-raycomputed tomographic apparatus will be exemplified as a medical imagingapparatus. X-ray computed tomographic apparatuses include various typesof apparatuses, e.g., a rotate/rotate-type apparatus in which an X-raytube and X-ray detector rotate together around a subject to be examined,and a stationary/rotate-type apparatus in which many detection elementsare arrayed in the form of a ring, and only an X-ray tube rotates arounda subject to be examined. The present invention can be applied to eithertype. In this case, the rotate/rotate type, which is currently themainstream, will be exemplified. In order to reconstruct one-slicetomogram data, projection data corresponding to one rotation around asubject to be examined, i.e., about 360°, is required, or (180°+viewangle) projection data is required in the half scan method. The presentinvention can be applied to either of these reconstruction schemes. Asmechanisms of converting incident X-rays into electric charges, thefollowing techniques are the mainstream: an indirect conversion typethat converts X-rays into light through a phosphor such as ascintillator and converts the light into electric charges throughphotoelectric conversion elements such as photodiodes, and a directconversion type that uses generation of electron-hole pairs in asemiconductor by X-rays and migration of the electron-hole pairs to anelectrode, i.e., a photoconductive phenomenon. As an X-ray detectionelement, either of these schemes can be used. In this case, the formertype, i.e., the indirect conversion type, will be exemplified. Recently,with advances toward the commercialization of a so-called multi-tubetype X-ray computed tomographic apparatus having a plurality of pairs ofX-ray tubes and X-ray detectors mounted on a rotating ring, relatedtechniques have been developed. The present invention can be applied toboth a conventional single-tube type X-ray computed tomographicapparatus and a multi-tube type X-ray computed tomographic apparatus.The single-tube type X-ray computed tomographic apparatus will beexemplified here.

FIG. 16 shows the arrangement of the main part of an X-ray computedtomographic apparatus according to this embodiment. The X-ray computedtomographic apparatus according to this embodiment includes a gantry2100. The gantry 2100 includes an annular rotating frame 2102. Arotation driving unit 2107 drives/rotates the rotating frame 2102 abouta rotation axis RA. An X-ray tube 2101 and an X-ray detector 2103 aremounted on the rotating frame 2102 so as to face each other. The X-raytube 2101 receives a tube voltage and filament current from a highvoltage generator 2109 through a slip ring 2108, and generates X-rays.The X-ray detector 2103 detects X-rays transmitted through the subjectand outputs an electrical signal reflecting the dose of incident X-rays.A preprocessing device 2106 receives a signal (pure raw data) outputfrom the X-ray detector 2103 through a data acquisition circuit 2104 anda noncontact data transmission device 2105. In the preprocessing device2106, a data storage device 2112 stores data having undergonesensitivity correction, logarithmic transformation, and the like (calledprojection data or raw data). An electrocardiograph 2203 and arespirometer 2204 are provided on or apart from the gantry 2100.

A gantry mount display 2201 is placed on or near the gantry 2100. Morespecifically, as shown in FIG. 17, the gantry mount display 2201comprising a liquid crystal panel and the like is placed on the housingsurface of the gantry 2100 at a position where the display does notbecome an X-ray blockage and can be visually recognized by the subjectinserted into an opening portion 2203, typically a cone-shaped portionaround the opening portion 2203. As shown in FIG. 18, the gantry mountdisplay 2201 may be suspended from the gantry 2100 through anarticulated arm 2221. A gantry loudspeaker unit 2202 is placed on ornear the gantry 2100. More specifically, the gantry loudspeaker unit2202 is placed on the housing surface of the gantry 2100 at a positionwhere the loudspeaker unit does not become an X-ray blockage and thesubject inserted in the opening portion 2203 can easily hear, typicallya cone-shaped portion around the opening portion 2203.

A scan controller 2110 controls the operations of the rotation drivingunit 2107, high voltage generator 2109, and the like to perform dataacquisition (scanning). A reconstruction device 2114 reconstructstomogram data on the basis of projection data stored in the data storagedevice 2112. The display device 2116 is provided to display mainlytomogram data. An operation device 2115 comprises a keyboard, mouse, andthe like and is used to input operator instructions.

A display/loudspeaker control unit 2205 controls the display of thegantry mount display 2201 and the audio output (voice output) of thegantry loudspeaker unit 2202. This embodiment is characterized by thedisplay of the gantry mount display 2201 and the audio output of thegantry loudspeaker unit 2202.

An audio item storage unit 2213 stores a plurality of audio files (voicefiles) associated with spoken instructions to a subject, which areordered in accordance with the progress of examination. Audio files areassociated with a plurality of examination stages representing theprogresses of examination and scan. For example, an audio file of themessage “hold your breath” to be played back at the time of breathholding imaging is prepared. The audio item storage unit 2213 stores aplurality of audio files associated with a music (an ambient music,healing music, or the like) having a relaxing effect regardless of anexamination instruction and the like, a reading, a soft narration, andthe like. These audio files of musical pieces having relaxing effectsand the like are associated with a relaxing period after the end ofbreath holding and the rest time between scans.

The display/loudspeaker control unit 2205 selectively reads out an audiofile from the audio item storage unit 2213 in accordance with a controlsignal representing an examination stage from the scan controller 2110.The loudspeaker unit 2202 then plays back the audio file.

A display item storage unit 2212 stores a plurality of image filesassociated with still images or moving images. At least one or aplurality of image files are associated with the respective audio filesstored in the audio item storage unit 2213. The display/loudspeakercontrol unit 2205 reads out, from the display item storage unit 2212, atleast one image file which is read out from the audio item storage unit2213 in accordance with a control signal representing an examinationstage from the scan controller 2110 and is associated with an audio fileto be played back, and causes the gantry mount display 2201 to displaythe image file. Ages and sexes may be associated with image files. Inthis case, among image files of the same kind, the image file of apreferred graphic pattern corresponding to an age and sex can beselectively displayed. For example, it is possible to display an imagefor an infant, as shown in FIG. 20.

A manager can perform various updating operations through the operationdevice 2115, e.g., storing a new audio file in the display item storageunit 2212, deleting an unnecessary audio file, and changing theassociation of an audio file with an examination stage. Likewise, themanager can perform various updating operations through the operationdevice 2115, e.g., storing a new image file in the display item storageunit 2212, deleting an unnecessary image file, and changing theassociation of an image file with an audio file. A storage managementunit (not shown) updates the storage unit 2212 and 2213 in accordancewith these updating operations.

Image files include character message files (FIGS. 21, 22, 24, 26, 28,29, 38, 39, and 41) expressing a spoken instruction to the subject, theprogress of a scan, the progress of examination, and the like incharacter messages. For Example, there are prepared text message filesindicating the time to the start of breath holding, the remaining timeto the end of breath holding, an instruction to stop breath holding, thetime to the start of a scan, a state indicating that a scan is beingperformed, the remaining time to the end of a scan, and the like. Evenif the subject fails to listen to a spoken instruction or cannot easilyunderstand it by voice, the subject can visually recognize theinstruction or can sequentially visually recognize the contents of thecurrent instruction.

In addition, image files include graphic pattern message files (FIGS.23, 25, 27, 30, 31, 40, and 42) for supplementing the contents ofinstructions by voice and text by using graphic patterns. For example,graphic pattern message files include the file of a graphic patternindicating how the subject breathes deeply and the file of a graphicpattern indicating how the subject holds a breath. In addition, graphicpattern message files include the file of a graphic pattern indicatingthe ratio of the remaining time of breath holding to the entire time ofbreach holding, typically a bar graph (FIG. 27), the file of a graphicpattern indicating the ratio of the remaining time to the examinationtime, typically a bar graph (FIG. 30), the file of a graphic patternindicating an examination time schedule together with the current timepoint, typically a bar graph (FIG. 31), the file of a moving imageschematically expressing how the X-ray tube is rotating (FIG. 40), thefile of a graphic pattern indicating the ratio of the remaining time tothe entire scan time, typically a bar graph (FIG. 42), the file of agraphic pattern indicating the ratio of the remaining rest time to thenext scan to the rest time between the current scan and the next scan,typically a bar graph, and the like.

FIGS. 43A, 43B, 43C, and 43D each also show an example of a breathholding instruction image (guidance image). FIG. 43A shows a real imageof a woman in her initial state of taking a deep breath. FIG. 43B showsa real image of the woman in a state of maintaining inspiration. FIG.43C shows a real image of the woman in a state of starting breathholding. FIG. 43D shows a real image of the woman in an expiration stateupon completion of breath holding. Face marks schematically indicatingan inspiration state, breath holding state, and expiration state,respectively, are displayed together with these real images. Inaddition, the remaining times of breath holding are displayed in threestages, namely, “more than 10 sec”, “10 sec or less”, and “five sec orless”.

FIG. 44 shows an example of an image indicating the progress ofexamination. This example shows a state in which a subject to beexamined is inserted into the gantry from the foot side using a topslide and the insertion posture of the subject with her arms being heldup to her head.

Furthermore, image files include, for example, the files of backgroundvideos (FIGS. 32 and 33) of sceneries prepared in advance as video fileshaving relaxing effects regardless of examination instructions. Imagefiles also include the file of animation (FIG. 34) aimed at infants andchildren in particular to suppress their body movement and keep themquiet during examination and the file of a video of a mother (FIG. 35)which is captured in advance or captured live by a TV camera 2210. Inaddition, it suffices to play back a favorite video stored in a memorydevice 2209 which the subject himself/herself has brought with him/her.

As described above, an audio file is played back in accordance with anexamination stage under the control of the display/loudspeaker controlunit 2205, and the operator can cancel the automatic mode of displayingimage files and select, as an audio or image source through theoperation device 2115, the memory device 2209, the TV camera 2210, or amicrophone 2211 which is connected through an input interface 2207 and aconnection terminal 2208. For example, displaying the selection windowshown in FIG. 37 allows to receive, from the subject, an instruction toselect audio data or video data at the time of relaxing before the startof examination.

The connection terminal 2208 is a general purpose standard terminal,which allows the subject to bring the memory device 2209 with him/her toa hospital upon checking his/her favorite music or video and play itback. Alternatively, selecting the TV camera 2210 and the microphone2211, which are placed in an operation room near an imaging room, assources makes it possible to, for example, show a video of a mother toher child or infant and give him/her various kinds of instructions byvoice.

FIGS. 19 and 20 show window examples on the gantry mount display 2201 atthe time of breath holding. When performing breath-holding examination,this apparatus plays back an audio file containing the message “holdyour breath” and displays a plurality of image files B-1, B-2, B-3, andB-4 associated with the audio file. The apparatus displays, for example,the video B-5 corresponding to a breath holding instruction aimed at aninfant, as shown in FIG. 20.

Note that the window on the gantry mount display 2201 can be dividedinto a display area B aimed at the subject, an area A aimed at theoperator (imaging engineer), and an area C aimed at both the subject andthe operator. The display area A displays a heart rate,electrocardiographic waveform, and the like. The display area C displayspatient information, imaging engineer information, hospital guideinformation, and advertisement information.

This embodiment allows the subject to easily understand which actionshe/she should take at various timings during examination, through voiceand image. The subject can therefore properly take actions, e.g., breathholding. In addition, since operators can easily change display contentsand voice contents, subjects can further easily understand which actionsthey should take in accordance with the characteristics of facilitieswhich they use. Furthermore, since the remaining time of breath holding,the time to the next scan, the remaining scheduled time of examination,and the like can be displayed, the anxiety of the patent can berelieved. Timely supplying audio and video data which promote relaxationcan promote the relaxation of the subject and stabilize examination. Inaddition, this embodiment allows to designate a device to be used amongthe microphone 2211, TV camera 2210, memory device 2209, and the likewhich are freely connected to the connection terminal 2208, as an audioor video source, in addition to the storage units 2212 and 2213, andhence can effectively promote relaxation in accordance with personalpreferences.

This embodiment can be modified as follows. As shown in FIG. 45, thegantry mount display 2201, the loudspeaker unit 2202, thedisplay/loudspeaker control unit 2205, the display item storage unit2212, and the audio item storage unit 2213 constitute a system (usernavigation system or respiration navigation system) 3000 independent ofthe X-ray CT apparatus, together with a designation unit 2214 and anediting unit 2215. The display/loudspeaker control unit 2205, displayitem storage unit 2212, audio item storage unit 2213, and editing unit2215 are accommodated in a gantry 2100. The designation unit 2214 ismounted on the housing of the gantry 2100 or is connected to it througha connector.

The user navigation system 3000 is connected to the X-ray CT apparatusthrough a plug 3001. Upon receiving a control signal from the scancontroller 2110 of the X-ray CT apparatus, the display/loudspeakercontrol unit 2205 of the user navigation system 3000 reads out the imagefile and audio file (to be generically termed as respiration guide datafiles) specified by the control signal from the display item storageunit 2212 and the audio item storage unit 2213. The display/loudspeakercontrol unit 2205 then causes the gantry mount display 2201 to performdisplay, and causes the loudspeaker unit 2202 to perform audio output.

The designation unit 2214 is an operation device which the user uses todesignate the insertion direction of a subject to be examined into thegantry of the X-ray computed tomographic apparatus, whether to raise orlower his/her arms, whether to use a contrast medium, and the type ofrespiration method to be used. A respiration guide data file editingunit is provided to edit respiration guide data files in accordance withthe insertion direction, whether to raise or lower the arms, whether touse a contrast medium, and the type of respiration method to be usedwhich are designated through the designation unit 2214.

FIG. 46 shows an examination information window displayed on the screenof a display device 2116 of the X-ray CT apparatus or the operationdevice 2115. This window displays the information of a control signaltransmitted from the scan controller 2110 of the X-ray CT apparatus tothe user navigation system 3000. The information of a control signalincludes a data code as information which specifies a display item andan audio item, the time of generation of the control signal, the type ofcontrol signal, and information indicating the results of execution ofdisplay and audio item outputs. The operator can check the display itemdisplayed on the gantry mount display 2201 and the audio item outputfrom the loudspeaker unit 2202 by seeing the information of the controlsignal.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. An X-ray computed tomographic apparatus comprising: a gantryincluding an X-ray tube which generates X-rays and an X-ray detectorwhich detects X-rays transmitted through a subject to be examined; atomogram generating unit which generates tomogram data on the basis ofan output from the X-ray detector; a breath detecting unit which detectsa respiration waveform representing a temporal change in respirationindex value associated with the subject; a regular respiration waveformgenerating unit which generates a respiration waveform with a regularrespiration cycle, the respiration waveform originating from thedetected respiration waveform; a breath instruction unit which providesbreath instruction information on the basis of the generated regularrespiration waveform; and wherein the breath instruction unit includes arespiratory sound generating unit which generates respiratory sound inaccordance with display of the regular respiration waveform.
 2. Anapparatus according to claim 1, wherein the display unit displays arespiration guide mark which moves relative to the displayed regularrespiration waveform.
 3. An apparatus according to claim 2, wherein thebreath instruction unit includes a respiratory sound generating unitwhich generates respiratory sound in synchronism with movement of therespiration guide mark.
 4. An apparatus according to claim 1, whereinthe regular respiration waveform is a combination of waveform elementsor waveform portions of the detected respiration waveform.
 5. Anapparatus according to claim 1, wherein the regular respiration waveformgenerating unit specifies a respiration waveform element of the detectedrespiration waveform which exhibits a highest frequency of appearance,and generates the regular respiration waveform by combining thespecified respiration waveform elements.
 6. An apparatus according toclaim 1, wherein the regular respiration waveform generating unitspecifies a waveform element of the detected respiration waveform whichcorresponds to a respiration cycle with a highest frequency ofappearance and exhibits a highest respiration depth, and generates theregular respiration waveform by combining the specified waveformelements.
 7. An apparatus according to claim 1, wherein the regularrespiration waveform generating unit specifies a waveform portion of thedetected respiration waveform which exhibits a smallest variation inrespiration cycle and generates the regular respiration waveform bycombining the specified waveform portions.
 8. An apparatus according toclaim 1, wherein the regular respiration waveform generating unitspecifies a plurality of waveform portions of the detected respirationwaveform which exhibit a smallest variation in respiration cycle andgenerates the regular respiration waveform by averaging the specifiedwaveform portions and combining the averaged waveform portions.
 9. Anapparatus according to claim 1, wherein the breath instruction unitincludes a display unit which is held on a housing of the gantrydirectly or through an arm and displays the generated regularrespiration waveform.
 10. A medical imaging apparatus comprising: animage generating unit which generates image data by imaging a subject tobe examined; a breath detecting unit which detects a respirationwaveform representing a temporal change in respiration index valueassociated with the subject; a regular respiration waveform generatingunit which generates a respiration waveform with a regular respirationcycle which originates from the detected respiration waveform; a breathinstruction unit which provides breath instruction information on thebasis of the generated regular respiration waveform; and wherein thebreath instruction unit includes a respiratory sound generating unitwhich generates respiratory sound in accordance with display of theregular respiration waveform.
 11. A breath instruction apparatuscomprising: a breath detecting unit which detects a respiration waveformrepresenting a temporal change in respiration index value associatedwith a subject to be examined; a regular respiration waveform generatingunit which generates a respiration waveform with a regular respirationcycle which originates from the detected respiration waveform; a displayunit which displays the generated regular respiration waveform; andwherein the breath instruction unit includes a respiratory soundgenerating unit which generates respiratory sound in accordance withdisplay of the regular respiration waveform.
 12. An X-ray computedtomographic apparatus comprising: a gantry including an X-ray tube whichgenerates X-rays and an X-ray detector which detects X-rays transmittedthrough a subject to be examined; a tomogram generating unit whichgenerates tomogram data on the basis of an output from the X-raydetector; a file storage unit which stores a plurality of audio filesand a plurality of image files which are associated with instructions tothe subject; an information storage unit which stores informationassociating the audio file and the image file with each of a pluralityof examination stages; an instruction information providing unit whichprovides instruction information to the subject on the basis of theaudio file and the image file which are associated with an examinationstage in accordance with a progress of the examination; and a changingunit which changes the association information in accordance with a userinstruction.
 13. An apparatus according to claim 12, wherein the audiofile and the image file stored in the storage unit can be updated. 14.An apparatus according to claim 12, wherein the associated informationstorage unit associates the audio file and the image file with an ageand/or sex of the subject as well as with the examination stage.
 15. Anapparatus according to claim 12, wherein the instruction informationproviding unit selects the audio file and the image file in accordancewith an age and/or sex of the subject as well as with the examinationstage.
 16. An apparatus according to claim 12, wherein the instructioninformation providing unit includes a display unit which displays theimage file, and the display unit is mounted on the gantry.
 17. Anapparatus according to claim 12, wherein the file storage unit stores aplurality of graphic pattern files for expressing a progress of theexamination by a graphic pattern in association with the progress of theexamination.
 18. An apparatus according to claim 12, wherein the filestorage unit stores a plurality of graphic pattern files associated withthe examination stage.
 19. An apparatus according to claim 12, whereinthe instruction information providing unit changes a playback volume ofthe audio file in accordance with the examination stage.
 20. Anapparatus according to claim 12, wherein the instruction informationproviding unit displays, in a bar graph, a ratio of an elapsed timesince a start of breath holding or a remaining time to a scheduledbreath holding time.
 21. An apparatus according to claim 12, whereinsaid plurality of image files stored in the file storage unit include avideo file having a relaxing effect which is irrelevant to theexamination.
 22. A medical imaging apparatus comprising: an imagegenerating unit which generates image data by imaging a subject to beexamined; a file storage unit which stores a plurality of audio filesand a plurality of image files which are associated with instructions tothe subject; an information storage unit which stores informationassociating the audio file and the image file with each of a pluralityof examination stages; an instruction information providing unit whichprovides instruction information to the subject on the basis of theaudio file and the image file which are associated with an examinationstage in accordance with a progress of the examination; and a changingunit which changes the association information in accordance with a userinstruction.
 23. A radiography system comprising an X-ray computedtomographic apparatus which scans a subject to be examined with X-rays,acquires projection data, and reconstructs an image, and a respirationnavigation apparatus which guides respiration operation for the subject,the respiration navigation apparatus including a storage unit whichstores a plurality of respiration guide data files for guiding therespiration operation, a read control unit which selectively reads outthe respiration guide data file from the storage unit in accordance witha control signal from the X-ray computed tomographic apparatus, and adisplay unit which displays the readout respiration guide data file, andthe X-ray computed tomographic apparatus including a control signalgenerating unit which controls scanning of the subject and generates thecontrol signal in synchronism with control on the scanning; a displayunit which displays a time of generation of the control signal, a typeof the control signal, and an execution result; a designation unit bywhich the user designates an insertion direction of the subject into agantry of the X-ray computed tomographic apparatus, whether to raise orlower arms, whether to use a contrast medium, and a type of respirationmethod, and a respiration guide data file editing unit which edits saidplurality of respiration guide data files in accordance with theinsertion direction, whether to raise or lower, whether to use acontrast medium, and the type of respiration method which have beendesignated.
 24. A system according to claim 23, wherein the respirationguide data file includes moving image information for instructingrespiration and icon information for instructing respiration.
 25. AnX-ray computed tomographic apparatus comprising: a gantry including anX-ray tube which generates X-rays and an X-ray detector which detectsX-rays transmitted through a subject to be examined; a tomogramgenerating unit which generates tomogram data on the basis of an outputfrom the X-ray detector; a breath detecting unit which detects arespiration waveform representing a temporal change in respiration indexvalue associated with the subject; a regular respiration waveformgenerating unit which generates a respiration waveform with a regularrespiration cycle, the respiration waveform originating from thedetected respiration waveform; a breath instruction unit which providesbreath instruction information on the basis of the generated regularrespiration waveform; wherein the breath instruction unit includes adisplay unit which is held on a housing of the gantry directly orthrough an arm and displays the generated regular respiration waveform;and wherein the breath instruction unit includes a respiratory soundgenerating unit which generates respiratory sound in accordance withdisplay of the regular respiration waveform.